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| author | Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> | 2012-01-23 15:54:52 -0500 |
|---|---|---|
| committer | Tony Luck <tony.luck@intel.com> | 2012-02-22 13:14:16 -0800 |
| commit | fadd85f16a8ec3fee8af599e79a209682dc52348 (patch) | |
| tree | 203da1b195a8c7d90c52537b501df4d21f34e23b /arch/x86 | |
| parent | d6126ef5f31ca54980cb067af659a360dfcca037 (diff) | |
| download | linux-stable-fadd85f16a8ec3fee8af599e79a209682dc52348.tar.gz linux-stable-fadd85f16a8ec3fee8af599e79a209682dc52348.tar.bz2 linux-stable-fadd85f16a8ec3fee8af599e79a209682dc52348.zip | |
x86/mce: Fix return value of mce_chrdev_read() when erst is disabled
Current kernel MCE code reads ERST at the first reading of /dev/mcelog
(maybe in starting mcelogd,) even if the system does not support ERST,
which results in a fake "no such device" message (as described in [1].)
This problem is not critical, but can confuse system admins.
This patch fixes it by filtering the return value from lower (ACPI) layer.
[1] http://thread.gmane.org/gmane.linux.kernel/1060250
Reported by: Jon Masters <jonathan@jonmasters.org>
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Huang Ying <ying.huang@intel.com>
Link: https://lkml.org/lkml/2012/1/23/299
Signed-off-by: Tony Luck <tony.luck@intel.com>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kernel/cpu/mcheck/mce.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c index 4979a5dfeba2..87c56ba8080c 100644 --- a/arch/x86/kernel/cpu/mcheck/mce.c +++ b/arch/x86/kernel/cpu/mcheck/mce.c @@ -1541,6 +1541,12 @@ static int __mce_read_apei(char __user **ubuf, size_t usize) /* Error or no more MCE record */ if (rc <= 0) { mce_apei_read_done = 1; + /* + * When ERST is disabled, mce_chrdev_read() should return + * "no record" instead of "no device." + */ + if (rc == -ENODEV) + return 0; return rc; } rc = -EFAULT; |